Centrifugal fan.



PATENTED APR. 23, 1907.

J. VBRNER.

OENTRIFUGAL FAN.

APPLICATION IILBD AUG. 2, 1906.

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J. VERNER.

GBNTRIPUGAL FAN.

APPLICATION FILED we. 2. 1906.

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J. VERNER.-

GENTRIPUGAL FAN.

AEPLIOATIOH FILED AUG. 2, 1906.

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-JOHN VERNER, OF cHARiToN, Iowa CENTRIFUGAL FAN.

To all whom it may concern.-

Be it known that I, JOHN VERNER, a citi-' following-is a specification.

This invention relates to centrifugal fans adapted for ventilating and other purposes, and-particularly. applicable for use in connecother places where large air volumes must be supplied. The fan, however, is not confined in its use or application.

' The invention contains several novel features which are believed to be new in the construction of centrifugal fans. The combination of all the improved features represents the invention in its entirety and greatest usefulness; yet either of these features, or some combination of them, has sufficient and specific value to materially increase the efficiency of revolution of any fan provided with such feature or features.

The first important feature consists of a straight plate fixed at right angles to the rear side of each radial blade and near the outer extremity of the latter, the purpose of this plate being to utilize with the power of the partial vacuum set up immediately in rear of the radial-blades when the fan is in motion. By using this plate attachment the air required to fill this partial vacuum will be taken through the central intake openings or eyes of the fan instead of being largely supplied from the air that has aladjacent to its periphery in the expansion chamber hereinafter set forth. Injurious eddies at the fansperiphery and the re-use of the air after its are also avoided by the provision of this plate structure. The plate structure also acts as a support for the air contained in the expansion chamber.

A second important feature of the invention consists of auxiliary intake openings located adjacent to and in rear of the side edges of each radial blade and )rovided with deflectors. The purpose of t ese openings and their equipments is to provide the most useful and direct means of drawing air into the fan to fill up the partial vacuum formed in the immediate rear of the radial blades when the fan is in motion, and also to facilitate the entrance of a large volume of air Specification of Letters Patent. Application filed August 2, 1906- Serial No. 328,922-

greater advantage passage through the fan Patented April 23, 1907.

into the body of the fan at a point where itcan be used to the best advantage, namely, at the forward portion of the space between the two adjacent blades.

The third important feature of the invention is the arrangement of the fan blades in series or sets of difierent lengths and so located with respect to the intakeopenings that a large flow of air through the fan can be produced and maintained while the forming of counter-currents and eddies in thefan is reduced to a minimum.

Other details of construction will be more fully hereinafter referred to.

In the drawing: Figure 1- is a side elevation of a fan embodying the features of the invention. body of the fan and particularly showing the plate attachment i to the radial straight blades. Fig. 3 is a view similar to Fig. 2 showing a slight modification. view similar to Fig. 1 showing a fan with ra dial straight blades with angularly disposed plates on the rear sides at their outer ends. Fig. 5 is a view similar to Fig. 2, illustrating the-use of the auxiliary intake connection with a fan having radial straight blades.

Similar numerals of reference are employed to indicate corresponding parts in the several views.

The fan is intended to be rotated by suitable mechanism in any manner desired and from any source of power, the direction of rotation being indicated by the arrow 1. The fan structurally embodies a shaft 2 on .which are secured hubs 3 and spi ers, n

eluding radially projecting arms 4. To the outer ends of the arms 4, and forming the' side portions of the body of the fan, are bolted, riveted, or otherwise aflixed, metallic sheets or plates 5, these plates being preferably made of sheet metal, and in practice will be also of separate sections united to form complete rings at their outer extremities. The outer edges of the side plates or rings coincide with the periphery of the fan. Secured to the inner or adjacent faces of the side plates are angle brackets or irons 6, to which are attached the fan blades.

Fig. 4 1s aopenings in Cooperating with the blades of the fan are intake openings 7, which are formed in the side plates, and arranged close to the rear of each opening is a deflector 8, including a top shield or guard 9, each deflector 8 standing at a slight forward angle of inclination and alle advantageously co-o erating with the blades of the fan, which wil now 'be specifically described. The number of blades used in the construction of the fan is preferably twentyfour, arranged in eight sets, but a greater or less number may be employed. These blades may either be straight, as shown by Fig. 2, or they may be partly curved and partly straight, as shown by Fig. 3. The blades are preferably arranged sets of three, des ignatr-id by the numerals 10, 11 and 12. blade is the shortest of the set, and extends froma point along the rear edge of the intake opening 7 rearwardl-y and outwardly to the periphery of the fan. The blade 11 is long r than the blade 10, and is arranged paror about parallel, to the latter blade. The blade 11 extends from the inner edge of the side sheets with which it cooperates in each instance adjacent to theouter limit of the fan eye or central opening 13 between the inner edges of the side plates and the centerof the fan, and from the inner edge of the side plates the blade 11 also extends rearwardly and outwardly to the periphery of the fan.

The blade 12 is the longest of the set, and

preferably projects inwardly beyond the side plates one-third of its length, and thus is 10- cated a considerable distance into the central intake opening or fan eye 13. If this blade 12 is straight, as shown by Fig. 2, its disposition is preferably radial, or about radial, and extends as set forth, but if this blade 12 is formed as shown by Fi 3 it will be arranged radially or about radially at its inner portion and the outer part thereof will curve rearwardly and outwardly to the periphery of the fan.

As shown by Fig. 2, a tangentially arranged plate 14 is rigidly secured to the side plates or sheets and to the rear side of the blade 12 inthe series of the blades 10, 11 and 12, the said plate 14 being disposed at a right angle to the blade 12. The plate 14 engages the blade 12 a short distance inwardly from the outer end of the latter and extends rearwardly, as shown. This plate 14 is not used with the curved blades shown by Fig. 3.

The main or central intake openings 13 are not circular in form, as is the usual contour thereof in ordinary fans, but have straight edges owing to the particular arrangement and shaping of the side plates, and communicating therewith are the s ecial or auxil- The- It is well known that the volumetric efficiency of fans is determined by the ratio between the cubical contents of the fan and the number of cubic feet of air delivered by it per revolution. To promote this efficiency the existence of the following favorable conditions is required :The intake openings should be so designed as'to facilitate the inflow of air and aid in securing a greater uniformity of supply to all parts of the fan. The eflecti've suction power of the fan should be as large as circumstances will permit. The air entering through the intake openings should pass through the 'fan without being retarded by eddies and counter currents. Re-entry of air from the expanding casing into the fan should be prevented. The construction of fan as heretofore set forth meets the above re uired favorable conditions.

The erip eral organization of the fan under t e present invention is such that the air after it has been conveyed into the expanding casing surrounding the fan is prevented from re-entering the latter; Air always moves from the point of greater density to that of less density, and as the air in the expanding casing is of greater density than the air entering the fan at the intake openings, and of least density just in rear of the blades, especially near the outer ends of the latter, it follows that, unless prevented, these oints of least density will be supplied, partia ly at least, from the air in the expanding casing. This defect is especially pronouncedin straight bladed fans. such re-entry of air, the plate 14 is provided, and in addition each of the blades 10 and 1 1 has a flange or narrow late 17 at its outer end. The auxiliary intake openings 7 with the rear deflectors and upper guards 9 also re 5 perform an important part in the effective operation of the fan, and these intake open ings and deflectors conjunctively cooperate with the special arrangement of the several series of blades and the plate 14 to overcome I I numerous deficiencies in -fans as heretofore constructed.

Having thus described the invention, what is claimed is:

1. A fan having radially arranged blades, 1 15 side plates extending to the periphery of the fan and having main intake openings at the center-of the fan and also provided with auxiliary intake openings adjacent to and in rear of the side edges of the blades, the inner ex- 120 tremities of the auxiliary intake openings communicating with the central main intake openings.

2. A fan having radially arranged blades,

side plates extending to the periphery of the 12 5 j acent to and in rear of the side edges of the 13 To avoid r00 blades and communicating at their inner portions with the main intake openings at the fan center, and deflecting devices at the rear and over the outer portions of the auxiliary intake openings.

3. A fan having radially arranged blades,

side plates extending to the periphery of the fan, the side plates having main intake openings formed therein at the center of the fan, and auxiliary intake openings adjacent to and in rear of the side edges of the radial blades and communicating at their inner portions with the said central main intake openings, deflecting devices at the rear and over the outer portions of the auxiliary intake openings, and angularly disposed plates cooperating with the rear sides of the outer ends of the blades.

4. A fan involving a plurality of blades arranged in series and differing inlength, the longer blades being radial with respect to the fan and the short-er blades tangential to the center of the fan, side plates connected to the blades and extending to the periphery of the fan, the side plates having main intake openings formed therein at the center of the fan and also provided with auxiliary intake openings communicating at their inner portions with the central main intake openings and located adjacent to the longest blade of each series, deflecting devices at the rear and'over the outer portions of the auxiliary intake openings, and angular plates cooperating with the outer ends of the blades.

5. A fan involving a plurality of blades arranged in series of different lengths, a portion of the blades being tangential of the center of the fan, side plates connected to the ends of the blades and extending'to the periphery of the fan and provided with main intake openings at the center of the fan and also with auxiliary intake openings in rotary relation to the fan center and communicating at their inner portions with the central main intake openings, and deflecting means located in rear of each of the auxiliary intake openings. 6. A fan. of the class set forth, involving a plurality of blades arranged in series diflering in length, side plates secured to the ends of the blades and extending to the periphery of the fan and forming rings around the periphery of the fan, main intake openings being formed at the center of the fan through the plates, the plates also having auxiliary intake openings radially arranged with relation to the center of the fan and located immediately in rear of the side edges of the longest blade of each series of blades, the longest blade of each series of blades extending inwardly into the main intake openings and the remaining shorter blades terminating at the outer wall of the central main intake openings, and deflectors at the rear portions of the auxiliary intake openings.

7. A fan of the class set forth, involving a plurality of blades arranged in series differing in length, side plates connected to the ends of the blades and having main intake open ings formed 'at the center of the fan, the side plates being also rovided with auxiliary intake openings ra ially arrangedwith respect tothe center of the fan and communicating at their inner portions'with the central main intake openings, the auxiliary intake openings being located immediately in rear of the side edges of the longest blades of each series, the longest blades of each series having portions thereof also radially disposed with relation to the center of the fan.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

JOHN VERNER.

Witnesses:

WM. HAVEN, F. W. TRosT. 

